My Rosy Barb's tail is cut after adding guppies. Is it fin nipping?

Keep her separated and maintain pristine water quality to aid in recovery. You can add some StressCoat and 1 teaspoon of plain aquarium salt (not table or Epsom salt) per gallon of water. Treat with salt for 14 days maximum then reassess fin condition. Once she has healed, return her to the tank. Try to keep them in groups of 4 or more.

A photo of the fish would be helpful if you can get one. It could be infection, injury or parasites. Any new fish, ideally, should be quarantined for at least 2 weeks before being staffed to the main tank. For now, quarantine the fish. Treat with a broad spectrum dewormer. You can find one in the aquarium section of the local Petco. Maintain pristine water quality and add in some plain aquarium salt (NOT table or Epsom salt). This will reduce stress, improve gill function, treat minor infection and aid in recovery. Dissolve 1 teaspoon of salt per gallon of water in a cup or two of tank water and gently pour it into the tank. Treat for no more than 14 days then reassess the condition

Thanks for reaching out about your fish. Water quality or aggression by other fish should be considered. Testing water quality for pH, ammonia, nitrite and nitrate, correcting any problems. The fins should re-grow is the problem is corrected. Good luck.

If it is an inappropriate medication, then it may cause more harm than good. Fin nipping can be caused by having too small a tank or incorrect ratio of males to females to name a couple reasons. Consider separating the one being nipped to give it opportunity to heal. Maintain pristine water quality to aid in recovery. Minor damage will heal on its own. Moderate or severe damage may require antibiotics to treat or prevent infection.

Keep her in the hospital tank until she heals. maintain adequate water quality and temperature via frequent water changes, filtration and the use of a small, submersible heater. Plain aquarium salt (NOT table or Epsom salt) can be used as a general tonic to reduce stress, increase gill function, treat minor infection and aid in recovery. Dissolve up to 1 teaspoon of salt per gallon of water. Treat for 10-14 days then reassess fin condition.

Thanks for reaching out about Limon and including photos. This part of the missing dorsal fin appears more trauma than infections, due to lack of abraded edges or signs of infection. Fins do re-grow. Maintain pristine water quality. Good luck.

It needs to be separated into a hospital tank by itself so it can be treated and heal. If you leave it in the main tank, the others will continue to pick and nip until it dies. Maintain pristine water quality and chemistry during treatment. You can use a broad spectrum antibiotic for 10-14 days to treat infection. You can find one, such as Maracyn 1 or 2, Kanaplex or Furan, in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.